Hydrocarbon fluid streams, including both liquid and gas streams, are often contaminated with sulfur and mercury compounds. Sorbents containing supported metal sulfides, such as cupric sulfide (CuS), have been used to scavenge mercury from hydrocarbon fluid streams. For example, U.S. Pat. No. 4,094,777 describes a solid mass that contains a carrier and sulfided copper as an absorbent for mercury from a gas or a liquid. CuS based materials for Hg removal are offered by Axens, Johnson Matthey (JM) and others for applications in the natural gas and hydrocarbon industries.
Sorbents containing supported metal oxides, such as cupric oxide (CuO), have been used to remove both sulfur and mercury from hydrocarbon fluid streams. For example, U.S. Pat. No. 7,645,306 describes an absorbent containing copper oxide (CuO) to adsorb sulfur and mercury.
It has been observed that the mercury scavenged from the fluid stream concentrates on the surface of the copper-based sorbent, creating a thin mercury-rich shell. As such, prior art sorbents suffer from at least two problems. First, the mercury-containing shell is brittle and tends to easily break free from the sorbent, resulting in the production of mercury-rich particulates. The resulting particulates create safety and environmental hazards. For example, movement of saturated sorbent beads during replacement may lead to the release of mercury into the environment. In addition, the release of particulates during production use, such as during bed disturbances, abrasion, or process upsets, will result in an increased pressure drop as the released particulates disrupt the flow of material around the sorbent beads.
Second, only the outer portion of the active copper material is used for mercury scavenging, resulting in poor utilization of the active component. Accordingly, there is a need for mercury or sulfur/mercury sorbents that (i) are capable of retaining their structure and are less likely to shed mercury-rich particulates and (ii) have a higher level of active component utilization.